Example 2.8: The following frequency distribution refers to the number of hours worked per month of 50 workers of a factory. Compute median and mode of the frequency distribution.
Number of hours worked: 30-55, 55-80, 80-105, 105-130, 130-155, 155-180, 180-205
Number of workers: 3, 4, 6, 9, 12, 11, 5